### The reaction rate

can be influenced by several factors.
A formula has been derived for reaction rate wherein the most important and most influencing factors are included.
The rate depends on the concentration of the reactants [ ] , on the division/superficion of the substance (homo and heterogeneous), on the temperature (oC or K), and on the possible presence of a catalyst.

V ≈ [concentration] x division x energy of the particles x catalyst.

In this way, a formula is not very usefull. It is a formula in words. We want numbers and symbols.
You can simplify the formula keeping some circumstances constant during the reaction, in such a way that only the (not constant) concentration do remain in the formula.
Thus we get a mathematical formula:

V = k·[conc.]n

1. V: is the rate;
2. k: includes the whole of factors kept constant;
3. n: is the coefficient of the reactant as in the reaction equation;
4. In this way the concentrations of every homogeneous substance appears in the formula. Heterogeneous substances are left out;
5. A reactopm where k has a high value, has 'strong' reactants;ntia'
6. A reaction where k has a low value, has 'weak' reactants.

Important with reaction rates is the reactivity of particles. There are particles with a very high reactivity, often called: 'radicals'. Those radicals are mad - generally spoken - under influence of light and have the peculiar thing that they possess unpaired electron(s).